Backscattered electron imaging of resin-embedded sections.

Area of Science:

• Microscopy
• Biological Imaging
• Electron Microscopy

Background:

• Scanning electron microscopes (SEM) offer greater focal depth than transmission electron microscopes, ideal for 3D surface structure visualization.
• Historically, SEM in biology focused on bulk specimens, but recent advances have expanded its applications.
• Backscattered electron (BSE) signals at low accelerating voltages now permit imaging of block and section faces in resin-embedded tissues.

Purpose of the Study:

• To review modern SEM techniques for 3D biological structure analysis.
• To highlight advances in section-face imaging and serial section SEM.
• To showcase the reconstruction of cellular and organelle 3D shapes.

Main Methods:

• Utilizing backscattered electron (BSE) signals for section-face imaging of resin-embedded tissues.
• Employing serial section scanning electron microscopy (SEM) for 3D reconstruction.
• Acquiring BSE-mode SEM images of consecutive ultrathin sections on solid substrates.

Main Results:

• Novel 3D imaging techniques like focused ion beam SEM and serial-block face SEM have been developed.
• Clear 3D reconstructions of cells and organelles are achievable through serial tomographic imaging.
• Section-face imaging and serial section SEM provide detailed insights into biological structures.

Conclusions:

• Modern SEM techniques, particularly BSE-based section-face imaging and serial section SEM, significantly advance 3D biological research.
• These methods enable unprecedented visualization and reconstruction of cellular and subcellular architectures.
• SEM continues to evolve, offering powerful tools for understanding complex biological forms in three dimensions.